In recent years, in color display devices, methods for improving display luminance have been proposed. As an example, there has been proposed a liquid crystal display device in which one unit pixel is constituted by arranging a red (R) pixel, a green (G) pixel, a blue (B) pixel and a white (W) pixel in one row.
In this liquid crystal display device, when an image is displayed indoors, transmissive light of the white pixel contributes to display. Thus, even if the backlight unit is driven at low luminance, the display luminance is enhanced and the visibility is secured. On the other hand, when an image is displayed outdoors, ambient light (e.g. sunlight) is reflected and glare occurs. Thus, in order to secure the visibility, it is necessary to drive the backlight unit at high luminance, leading to an increase in power consumption.